Analysis of gain distribution in a slab-type rf-excited CO2 laser medium

Spatially resolved gain distributions of RF excited slab CO2 laser medium are measured in four lines of P branch (such as P(14),P(20),P(26),P(30)) to examine the difference between the center of slab electrodes spacing (alpha discharge region) and near the electrode region (sheath). For measurement low7 power C02 laser beam is put through the spacing of the slab electrodes and passed beam is detected as a cross-sectional image by pyro-electric detector arrays each of which has a resolution of 0.1*0.1mm. The result of P(20) line was 0.4%/cm at the center and down to half near the electrode. And from measured four lines of gain gas temperature (CO2 rotational temperature) is calculated to be 400K at the center and increasing to about 550K near the electrode assuming distribution of rotational levels of each line is accord to a Botzmann distribution. And by solving the heat transfer equation using obtained temperature distribution, heat generation is found to be occurred near the electrode.